1. Field of the Invention
This invention relates to magnetoresistive (MR) sensors and more particularly to MR sensor devices and methods of fabrication thereof.
2. Description of Related Art
Kim et al., U.S. Pat. No. 5,608,593 for “Shaped Spin Valve Type Magnetoresistive Transducer and Method for Fabricating the Same Incorporating Domain Stabilization Technique” shows a spin valve (SV) with a permanent magnet with a non-magnetic (e.g., Cr) underlayer (Separation layer). (See col. 5, lines 15 to 25.)
Ravipati, U.S. Pat. No. 5,708,358 for a “Spin Valve Magnetoresistive Transducers Having Permanent Magnets” has thin film layers of ferromagnetic material separated from each other by a nonmagnetic spacer. The direction of magnetization of one thin ferromagnetic layer is pinned by a permanent magnetic layer. Another permanent magnetic layer is located adjacent to the other thin film layer to provide longitudinal biasing.
Mauri, U.S. Pat. No. 5,796,561 for a “Self-biased Spin Valve Sensor” discloses a Spin Valve (SV) MagnetoResistive (MR) sensor with a free layer separated from a pinned layer by a spacer layer.
Takada et al., U.S. Pat. No. 5,828,527 for a “Thin Film Magnetic Head Having Magnetic Resistance Effect Stabilizing Layer” describes a thin film magnetic head with a magnetoresistance effect stabilizing layer with an underlayer of Ta or oxides of Al or Si, a buffer layer of chromium (Cr), a separation layer of Cr or Ta and a hard magnetic layer.